The goal of this work is to develop novel inhibitors of HIV-1 integrase (IN) as potent anti-HIV therapeutic drugs. Although combination therapy, which uses two or more drugs simultaneously to inhibit HIV activity, can reduce the HIV virus to undetectable levels in the blood of many HIV-positive patients, the viruses in T cells are still capable of replicating and infecting other cells. The development of new agents against HIV-1 IN, which may eliminate HIV-1 from intracellular sites would be a major advance in the treatment of HIV infection. The newly designed oligonucleotide, T30695, has shown effective interaction with HIV-1 IN in vitro (IC50 = 50 nM), and it may have the potential of stopping replication of HIV-1 virus by blocking integration in vivo. In order to improve the efficiency of its inhibition of HIV-1 IN activity for preclinical and phase I tests, T30695 will be used as a lead compound to design and select novel candidates for anti-HIV therapies with stronger inhibition of HIV-1 IN. SA 1. The structure-based design of inhibitors of HIV-1 IN will be performed using 3D molecular modeling based upon the molecular model of the T30695-IN complex, which was constructed from X-ray crystal and NMR structures of HIV-1 IN and T30695. These candidates, stored in a database, will be synthesized for further tests. SA 2. Measurement of HIV IN inhibition (IC50) of the rationally designed candidates will be carried out with a 96-well HIV-1 scintillation proximity assay (SPA). The inhibition of HIV-1 replication (EC50) will be measured in a virus culture assay, using the candidates with the lowest IC50 values, as assessed by SPA. SA 3. The biophysical characteristics, including 3D structure, of the rationally designed candidates for HIV-1 IN inhibition will be determined by NMR, modeling, CD, UV, and kinetics. Then, by combining the biophysical information with the anti-HIV activity, IC50 and EC50, a 3D QSAR (quantitative structure-activity relationships) will be conducted to select the best bioactive candidate as a potent inhibitor of HIV-1 IN for preclinical and phase I tests.